(1) Field of the Invention
This invention relates to an apparatus for the control of acceleration and deceleration of an automobile in motion during the course of so called "autocruise," i.e. the course of the automobile's travel at the automatically controlled optimum speed. More particularly, this invention relates to an apparatus for the control of acceleration and deceleration of an automobile in motion during the course of auto-cruise, designed to effect smooth control of the increase and decrease in the real speed of the automobile in the status of control of acceleration and deceleration, and to permit smooth transition from the status of acceleration and deceleration to the status of constant-speed cruise or vice versa.
(2) Description of Prior Art
To control acceleration of an automobile in motion during auto-cruise, there may be conceived an idea of increasing the opening angle of the throttle in response to the input of on acceleration signal and, on disappearance of the acceleration signal, fixing the position of the throttle as it exists at that very moment.
In contrast, to control deceleration during auto-cruise, there may be conceived an idea of decreasing the opening angle of the throttle aperture to almost zero, or to the level used for idling operation, in response to the input of a deceleration signal and, on disappearance of the deceleration signal, increasing the opening angle of the throttle to fix the position of the throttle so that it suits the real speed of travel at that very moment thereby to effect required resumption of the constant-speed cruise.
As well known through experience, however, there occurs considerable lag between the time the opening angle of the throttle is increased or decreased and the time the real speed of the automobile's travel correspondingly rises or falls.
When using the method for the control of deceleration described above, the opening angle of the throttle must be increased an excessive amount in effecting the resumption of constant-speed auto-cruise after the disappearance of deceleration signal, with the inevitable result that the attempted transition from deceleration to constant-speed cruise actually produces an acceleration which occurs so sharply as to detact from driving performance, and this also tends to induce detrimental phenomena such as hunting and overshoot in the real speed of cruise after the resumption of auto-cruise.
Further, when using the method for the control of acceleration described above, the initial stage of acceleration is so small as to irritate the driver of the automobile and, even after disappearance of the acceleration signal, the increase in the real speed of cruise continues to exist to a point where there may ensue an overshoot in the real speed of crusise.